Caesar's Gallic Wars (58-50 BC): The Roman Conquest of Gaul

The Gallic Wars were the campaigns in which Julius Caesar conquered Gaul between 58 and 50 BC, bringing the lands of modern France, Belgium and neighbouring regions under Roman rule. Fought with speed and ruthlessness, and recorded by Caesar himself in his Commentaries, they made him rich, famous and the commander of a devoted army. For the Gauls they meant defeat, mass death and enslavement, and the beginning of five centuries of Roman rule that shaped the languages and culture of Western Europe.

Background: Gaul and Rome before Caesar

Romans had long feared the Gauls, the Celtic-speaking peoples north of the Alps, since the Gallic sack of Rome around 390 BC. By the late second century BC Rome controlled northern Italy (Cisalpine Gaul) and a strip of southern France, the province of Transalpine Gaul, later called Narbonensis or simply “the Province”, from which Provence takes its name.

Beyond it lay “long-haired Gaul” (Gallia Comata), divided among dozens of peoples such as the Aedui, Arverni, Sequani, Helvetii and the Belgic tribes of the north. Many lived in fortified towns called oppida, minted coins and traded with the Mediterranean. Rivalries among them, especially between the Aedui, who were allies of Rome, and the Arverni and Sequani, gave Rome opportunities to intervene.

Caesar arrived as governor in 58 BC thanks to the First Triumvirate, his political pact with Pompey and Crassus, which gave him Cisalpine Gaul, Illyricum and Transalpine Gaul for five years. He was deeply in debt and needed both wealth and military reputation.

The campaigns year by year

58 BC: the Helvetii and Ariovistus. The Helvetii, from what is now Switzerland, began a mass migration westward. Caesar refused them passage through the Province, pursued them and defeated them near Bibracte, the Aeduan oppidum on Mont Beuvray in Burgundy. He then turned against Ariovistus, king of the Germanic Suebi, who had been invited into Gaul by the Sequani, and drove his forces back across the Rhine after a battle probably fought in Alsace.

57 BC: the Belgae. Caesar marched north against the Belgic peoples. At the river Sabis (probably the Sambre) the Nervii surprised his army while it built camp, and Caesar describes himself seizing a shield and rallying the front line. The Romans won, and the Atuatuci were punished after resisting: Caesar says 53,000 of them were sold into slavery.

56 BC: the Atlantic coast. The Veneti of Brittany, a seafaring people, rose against Roman demands. Caesar built a fleet, and his commander Decimus Brutus defeated their ships, probably in Quiberon Bay, by cutting their rigging with hooked poles. Caesar had the Veneti’s leaders executed and the rest sold. Publius Crassus, son of the triumvir, subdued Aquitania in the south-west.

55 BC: the Rhine and Britain. Two Germanic peoples, the Usipetes and Tencteri, crossed the Rhine. Caesar detained their envoys during a truce and then attacked their camp, killing very many, including women and children. In Rome, Cato proposed handing Caesar over to the Germans for breaking faith. Caesar then built a timber bridge across the Rhine in about ten days, crossed briefly as a show of strength and, late in the season, made the first of his invasions of Britain.

54-53 BC: revolt in the north-east. After a second expedition to Britain, Caesar’s legions were spread out in winter quarters. The Eburones under Ambiorix lured out a legion and a half under Quintus Titurius Sabinus and Lucius Aurunculeius Cotta and destroyed it, and the Nervii besieged the camp of Quintus Cicero, brother of the orator, until Caesar relieved him. In 53 BC Caesar ravaged the lands of the Eburones and crossed the Rhine a second time.

How Caesar won. Caesar’s army grew from four legions at the start of 58 BC to around ten, roughly 40,000 to 50,000 legionaries plus allied cavalry, much of it Gallic or Germanic. Its advantages were discipline, engineering and logistics: legionaries could build fortified camps every night, bridge rivers and dig siege works on a scale no Gallic force could match. Just as important were Gallic divisions. Caesar exploited rivalries between peoples, took hostages from the leading families and relied on allies such as the Aedui and Remi for grain and cavalry, so that for most of the war he never faced a united enemy.

Vercingetorix and the great revolt of 52 BC

In early 52 BC, with Caesar south of the Alps and Rome in turmoil, the Carnutes killed Roman traders at Cenabum (Orléans). A young Arvernian noble, Vercingetorix, was proclaimed king and united most of Gaul, even including, eventually, the Aedui.

Vercingetorix adopted a scorched-earth strategy to starve the Romans. Caesar stormed Avaricum (Bourges), claiming that of some 40,000 inhabitants only about 800 escaped. He was then repulsed with heavy losses at Gergovia, the Arverni’s own stronghold near modern Clermont-Ferrand, his only serious defeat in Gaul.

The war was decided at Alesia, near modern Alise-Sainte-Reine in Burgundy. Caesar surrounded Vercingetorix’s army with siege lines and then built a second, outward-facing line against a huge Gallic relief army. After several days of fighting in late September 52 BC the relief army was beaten and Vercingetorix surrendered. The siege is covered in detail in Siege of Alesia.

The last resistance, 51-50 BC

Fighting continued in 51 BC against the Bellovaci, Carnutes and others. At Uxellodunum in the south-west, Caesar cut off the water supply of the last defenders and, after their surrender, had the hands cut off all who had borne arms, as a warning to others. By 50 BC Gaul was pacified. The conquered territory, about the size of modern France and Belgium together, was organised into provinces in the following decades.

Key people

• Julius Caesar (100-44 BC): Governor and commander, whose speed of movement and willingness to take risks repeatedly surprised his enemies.
• Vercingetorix (c. 82-46 BC): Leader of the united Gallic revolt of 52 BC; after Alesia he was kept prisoner for six years, displayed in Caesar’s triumph in 46 BC and then executed.
• Ariovistus: Germanic king defeated by Caesar in 58 BC.
• Ambiorix: Leader of the Eburones who destroyed a Roman force in 54 BC and was never captured.
• Titus Labienus: Caesar’s most able deputy in Gaul, who later sided with Pompey in the civil war.

The human cost

Ancient writers give staggering figures. Plutarch says Caesar fought against three million men, killed one million and enslaved another million. Pliny the Elder reports that Caesar himself claimed 1,192,000 enemy dead in his wars, not counting the civil wars. These numbers cannot be verified and are probably inflated, but historians agree that the conquest killed and enslaved people on a massive scale and devastated whole communities.

Enslaved captives were sold to traders who followed the army, and the profits, along with plundered gold, made Caesar one of the richest men in the Roman world. His soldiers, enriched and loyal, became the instrument he would use against the Republic.

Caesar’s Commentaries

Caesar described the war in the Commentaries on the Gallic War (De Bello Gallico), seven books covering 58-52 BC, written in the third person in plain, rapid Latin; his officer Aulus Hirtius added an eighth for 51-50 BC. They are a primary source of great value, including early descriptions of Gaulish society, druids and Germanic peoples, but they are also political self-justification, sent to an audience in Rome. Readers should remember that almost everything we know about the war comes from the victor.

For centuries the Commentaries were a standard text for learning Latin, and their opening words, “Gallia est omnis divisa in partes tres” (“All Gaul is divided into three parts”), are among the most familiar in the language.

Consequences and legacy

The conquest gave Caesar the army and resources to cross the Rubicon in 49 BC and win the civil war, ending the Roman Republic in all but name; see Caesar Crosses the Rubicon. It also moved Rome’s frontier to the Rhine and opened the way to Britain.

In the long term, Gaul became one of the most prosperous and Romanised parts of the empire. Latin replaced the Gaulish language, eventually developing into French, and Roman roads, towns and law shaped the region. In the nineteenth century Vercingetorix became a French national hero: Napoleon III sponsored excavations at Alise-Sainte-Reine and a colossal statue there in 1865. The comic series Asterix, launched in 1959, playfully imagines one Gaulish village still holding out.

Timeline

• 58 BC: Caesar becomes governor; defeats the Helvetii near Bibracte and Ariovistus in Alsace.
• 57 BC: Campaign against the Belgae; victory over the Nervii at the Sabis.
• 56 BC: Naval victory over the Veneti in Brittany; Aquitania subdued.
• 55 BC: Massacre of the Usipetes and Tencteri; first Rhine bridge; first expedition to Britain.
• 54 BC: Second expedition to Britain; a legion and a half destroyed by the Eburones.
• 53 BC: Punitive campaigns in north-east Gaul; second Rhine crossing.
• 52 BC: Great revolt under Vercingetorix; Avaricum, Gergovia and Alesia.
• 51 BC: Siege of Uxellodunum.
• 50 BC: Gaul pacified; Caesar’s command nears its end amid conflict in Rome.

Why it matters

The Gallic Wars turned Caesar into the most powerful man in Rome and so helped bring down the Republic. They also redrew the map of Europe, binding Gaul to the Mediterranean world for centuries and laying foundations for modern France, while costing the lives and freedom of a vast number of people.